The present invention relates to a method for manufacturing electronic parts and an apparatus for manufacturing thin films.
Presently, thin films are used in a very wide range of products, for example, wrapping materials, magnetic tapes, capacitors, and semiconductors. Without these thin films, recent technologies for achieving a high performance and a small size cannot be explained. At the same time, various methods for forming a thin film have been developed to satisfy the industrial demands. For example, continuous taking-up vacuum evaporation, which is advantageous for high-speed mass production, is performed to manufacture thin films for use in wrapping paper, magnetic tapes, capacitors and the like.
In this case, a thin film having the desired properties can be formed by selecting an evaporation material and a substrate material according to the purpose of the thin film to be formed and, if necessary, introducing a reactive gas into a vacuum vessel and forming the thin film with an electric potential provided on the substrate. For example, in the manufacture of a magnetic recording medium, a long magnetic recording medium can be obtained by using an evaporation material comprising a magnetic element, such as Co, Ni, or Fe, and performing a reactive evaporation while introducing an oxygen-containing gas into the vacuum vessel.
In a semiconductor, a thin film is formed mainly by sputtering. Sputtering is effective especially for forming a thin film using a ceramic-based material. A ceramic thin film having a thickness of several xcexcm or more is often formed by coating and firing. A ceramic thin film having a thickness of 1 xcexcm or less is often formed by sputtering.
On the other hand, a coating method is used for forming a thin film using a resin material. Reverse coating or die coating is commercially used. In general, the coating of a material that is diluted with a solvent is performed, and then the material is dried for hardening. The lower limit of the thickness of the resin thin film formed by these methods is often around 1 xcexcm though it depends on the material. A resin thin film having a smaller thickness is often difficult to obtain with these methods. Since the thickness of the coating film immediately after coating is several xcexcm or more with a general coating process, diluting with a solvent is necessary for forming a very thin resin film, and a resin thin film having a thickness of 1 xcexcm or less often cannot be obtained with such a process. Furthermore, diluting with a solvent is not preferable from the viewpoint of environmental protection in addition to the fact that defects easily occur in the coating film after drying. Accordingly, a method for forming a resin thin film without diluting with a solvent and a method for obtaining a very thin resin film stably are desired. As these methods, a method for forming a resin thin film under vacuum is proposed. With this method, a resin material is evaporated under vacuum and attached to a support. According to this method, a resin thin film without void defects can be formed, and diluting with a solvent is not necessary.
Various composite thin films, which cannot conventionally be obtained, can be obtained by laminating a ceramic or resin thin film and a different type of thin film. The industrial use field of the composite thin films is very diversified. Among them, chip-shaped electronic parts are very promising. Capacitors, coils, resistors, capacitive electric cells, or composite parts thereof, or the like can be formed with a very small size and a high performance by laminating thin films. The merchandizing and market expansion of these products have started already.
It is needless to say that electrodes are indispensable for obtaining electronic parts. In electronic parts using a metal thin film, a metal thin film having a different electric potential can be formed by patterning a metal thin film. That is, complicated electronic parts can be formed by dividing a metal thin film into plural portions with patterning portions (portions where the metal thin film is not formed) defined as insulation regions and laminating the metal thin film and an insulating thin film.
FIG. 4 is a schematic view of an example of an apparatus for manufacturing electronic parts by laminating thin films. As shown in FIG. 4, a device 8 for manufacturing a metal thin film, a device 9 for manufacturing an insulating thin film made of a resin material or the like, a patterning material-applying device 11 for patterning the metal thin film, and the like are located around a cylindrical cooling can 7. These devices are housed in a vacuum vessel 5 and maintained at a predetermined degree of vacuum by an evacuation system 6 comprising a suction pump or the like. Then, a thin film laminate in which insulating thin films and patterned metal thin films are alternately laminated is formed on the outer periphery of the cooling can 7 by rotating the cooling can 7 in the arrow direction. In FIG. 4, the reference numeral 10 denotes a hardening device for hardening the insulating thin film to a predetermined hardness, and the reference numeral 12 denotes a patterning material-removing device for removing the extra patterning material after forming the metal thin film.
The thus formed thin film laminate is separated from the cooling can 7. Then, the laminate is cut to a required size for each electronic part and provided with external electrodes to form many electronic parts.
In addition, a method called oil margin or the like can be used to obtain the patterned metal thin film. This method utilizes the fact that the metal thin film is not formed on the patterning material when the metal thin film is formed by evaporation or the like after previously forming the patterning material thinly. In the thus formed metal thin film, the patterning portions are removed. Therefore, a metal thin film having the desired pattern can be formed. For example, many capacitors having a cross-sectional structure as shown in FIG. 3 can be obtained by switching the patterning position when repeating the alternate lamination of the metal thin film and the resin thin film with the apparatus as shown in FIG. 4, and cutting the laminate later.
However, the yield of electronic parts obtained by the above methods decreases because of defects such as cracking that occurs when the thin film laminate is separated from the support such as a can. In addition, such cracking deteriorates the reliability of the electronic parts significantly. Furthermore, the operation of the apparatus should be stopped and the vacuum atmosphere lost every time the thin film laminate is separated from the support. Therefore, the rate of film-forming operation of the apparatus decreases.
In order to solve the above problems in the conventional methods for manufacturing a thin film laminate for electronic parts, it is an object of the present invention to provide a method for manufacturing electronic parts that provide a high productivity and a high reliability. It is another object of the present invention to provide a manufacturing apparatus that can manufacture a highly reliable thin film laminate with a good productivity.
In order to achieve the above objects, a method for manufacturing electronic parts according to a first aspect of the present invention includes the steps of forming a laminated thin film on a support to which a mold releasing agent is previously applied and separating the laminated thin film from the support. According to the first aspect, since the mold releasing agent is applied to the support before forming the laminated thin film on the support, damage such as cracking is avoided in the laminated thin film when separating the laminated thin film from the support after forming the laminated thin film. Thus, electronic parts can be provided in a high yield and with high reliability. Accordingly, the manufacturing method of the present invention is suitable for the mass production of high-performance electronic parts including high-performance capacitors.
In the first aspect, when a plurality of the laminated thin films are laminated, a mold releasing agent may be applied to the surface of the laminated thin film during the lamination. According to this aspect, more laminated thin films for electronic parts can be obtained in a continuous lamination step by laminating a predetermined number of the laminated thin films and separating the laminated thin films at the surface to which the mold releasing agent is applied. In addition, damage such as cracking is avoided during the separation. Therefore, highly reliable electronic parts can be manufactured with a better productivity.
A method for manufacturing electronic parts according to a second aspect of the present invention is a method for manufacturing electronic parts having at least a metal thin film and an insulating thin film, including the steps of laminating two or more of the metal thin films and two or more of the insulating thin films on a support to form a laminate and separating the laminate in the thickness direction. According to the second aspect, since a plurality of laminates for electronic parts can be laminated in the thickness direction, the productivity of electronic parts improves. Thus, the present invention is suitable for the mass production of high-performance electronic parts including high-performance capacitors.
In the second aspect, it is preferable that a mold releasing agent is applied after laminating a predetermined number of the metal thin films and the insulating thin films and that a predetermined number of the metal thin films and the insulating thin films are further laminated. According to the preferable aspect, damage such as cracking is avoided during the separation of the laminate by applying the mold releasing agent to the separation surface. Therefore, electronic parts can be provided in a high yield with high reliability.
In the second aspect, it is preferable that the manufacturing method further includes the step of applying a mold releasing agent to the support prior to the step of forming the laminate. According to the preferable aspect, since the mold releasing agent is applied to the support, damage such as cracking does not occur in the laminate when separating the laminate from the support. Thus, electronic parts can be provided in a high yield with high reliability.
In the second aspect, it is preferable that the metal thin films and the insulating thin films are continuously formed under vacuum without destroying a vacuum atmosphere. In addition, it is preferable that the formation of the metal thin films and the insulating thin films and the application of the mold releasing agent are continuously performed under vacuum without destroying a vacuum atmosphere. Here, destroying a vacuum atmosphere means that the operation of returning to the atmospheric pressure is not performed and does not include a permissible decrease (fluctuation) in the degree of vacuum. According to the preferable aspect, electronic parts can be manufactured with a good productivity. In addition, since the oxidation of the metal thin films and the contamination of foreign substances into the laminate, which are caused by destroying the vacuum atmosphere, can be prevented, the decrease of the yield can be prevented, and highly reliable electronic parts can be obtained.
In the first and the second aspect, it is preferable that the application of the mold releasing agent is performed by a process selected from the group consisting of evaporation, spraying, sputtering, and a combination thereof. According to the preferable aspect, since the application of the mold releasing agent can be performed stably and reliably, the laminate can be separated easily. Thus, the decrease of the yield can be prevented, and highly reliable electronic parts can be obtained.
An apparatus for manufacturing a thin film according to the present invention includes a vacuum vessel, a vacuum pump for maintaining a predetermined degree of vacuum in the vacuum vessel, a support located in the vacuum vessel, a metal thin film-forming device for forming a metal thin film directly or indirectly on the support, an insulating thin film-forming device for forming an insulating thin film directly or indirectly on the support, and a mold releasing agent-applying device for applying a mold releasing agent to the surface of at least one of the support, a formed metal thin film, and a formed insulating thin film. According to this aspect, since the manufacturing apparatus includes the mold releasing agent-applying device for applying a mold releasing agent to the surface of the support, the metal thin film, or the insulating thin film, the mold releasing agent can be applied before or during lamination. Thus, the obtained thin film laminate can be separated easily from the support, or the laminate can be divided easily in the thickness direction. Damage such as cracking in the laminate during the separation or the division is avoided. Accordingly, a highly reliable thin film laminate can be manufactured efficiently.